1. Field of the Invention
This invention relates to a technique for processing copyright information in recording apparatus such as digital video cassette recorders (refer to as DVCR hereinafter) provided with a digital interface based on IEEE1394 format and computers.
2. Description of the Related Art
Commercial DVCRs which record/reproduce digitized video signals and audio signals have been commercially available. Such DVCR is provided with an interface for inputting and outputting video signals and audio signals as they are digital. Therefore, digital dubbing is possible between DVCRs provided with a digital interface.
The digital interface described herein above is arranged in accordance with IEEE1394. In audio and video signal transmission protocol of IEEE1394, a digital interface transmits signals in the clear based on the concept that transmission apparatus side and receiving side deal with copyright protection. Therefore a digital interface transmits signals without copyright information.
Content sent by way of a digital interface is divided into two main classes, namely dynamic image signals and other signals (such as computer data and programs). It is required to manage copyright in all apparatus including computers in the case of dynamic image signals. However, in the case of an apparatus such as a computer in which data are writable using software, copy management information itself can be rewritten.
The present invention has been accomplished in view of such problem. It is an object of the present invention to provide a method for protecting copyright in which an apparatus capable of rewriting copy management information, such as a computer, cannot accept signals other than copy free signals.
In order to solve the above-mentioned problem, the method for copyright protection in accordance with the present invention is the copyright protection method of digital signal to be inputted to a digital recording apparatus provided with a digital interface, in a header of a transmission frame of the digital signal to be transmitted a copyright protection information is contained, the copyright protection information restricts recording of the digital signal to be inputted to the digital recording apparatus, wherein the copyright protection information includes the copy free information for indicating to the digital recording apparatus that the digital signal is copy free, and the information for indicating to the digital recording apparatus so that the digital recording apparatus performs copy management in compliance with the copyright information included in the content of the transmitted transmission frame.
A medium in accordance with the present invention is the medium which receives content including a digital signal for performing copyright protection, in a header of a transmission frame of the digital signal to be transmitted a copyright protection information is contained, and the copyright protection information restricts recording of the digital signal to be inputted to the digital recording apparatus, wherein the copyright protection information includes the copy free information for indicating to the digital recording apparatus that the digital signal is copy free, and the information for indicating to the digital recording apparatus so that the digital recording apparatus performs copy management in compliance with the copyright information included in the content of the transmitted transmission frame.
The digital recording apparatus in accordance with the present invention is the digital recording apparatus provided with a digital interface, wherein the digital recording apparatus has a means for detecting the copyright protection information provided in a transmission header of a transmission frame of a digital signal inputted through the digital interface, and a means for taking in the transmission frame and for allowing recording processing if the copyright protection information indicates copy free of the digital signal.
The control IC in accordance with the present invention is the control IC for controlling a link layer of a digital interface mounted on a digital recording apparatus provided with the digital interface, wherein the control IC has a means for detecting the copyright protection information provided in a transmission header of a transmission frame of a digital signal inputted through the digital interface, and a means for taking in the transmission frame and for indicating recording processing to the digital recording apparatus if the copyright protection information indicates copy free of the digital signal.
According to the present invention, a recording apparatus which does not perform processing in compliance with the copyright information receives transmission frames only when the copyright protection information in a transmission header indicates copy free. A recording apparatus which performs processing in compliance with the copyright information accepts transmission frames when the copyright protection information in the transmission header indicates copy free, and when the copyright protection information in the transmission header indicates compliance with the copyright information contained in the content of the transmission frame, the copyright information in the content is fetched based on the signal format type information of the transmission header.